Use this first for any question about AGILEX hardware: pinouts, CAN
protocol details, baud rate, firmware upgrade, error codes, LED/beep
meanings, installation, calibration, SDK usage.
Args:
query: Chinese or English keywords. Include the product name
(piper / pika / nero / ranger / limo / scout / bunker / hunter /
tracer / umr) plus the concept, e.g. "piper CAN 波特率".
limit: 1-25 results, default 8.
space: optional space slug or name fragment to narrow the search,
e.g. "agx-chassis-manual-cn-en" or "底盘使用手册".
Returns JSON: {query, count, results:[{doc_id,title,space,url,score,chars,snippet}]}.
``doc_id`` is what ``get_doc`` expects.